/*!
 * Crypto-JS v1.1.0
 * http://code.google.com/p/crypto-js/
 * Copyright (c) 2009, Jeff Mott. All rights reserved.
 * http://code.google.com/p/crypto-js/wiki/License
 */
(function () {

// Shortcut
    var util = Crypto.util;

    var MARC4 = Crypto.MARC4 = {

        /**
         * Public API
         */

        encrypt: function (message, password) {

            var

            // Convert to bytes
                m = util.stringToBytes(message),

            // Generate random IV
                iv = util.randomBytes(16),

            // Generate key
                k = Crypto.PBKDF2(password, util.bytesToString(iv), 32, {asBytes: true});

            // Encrypt
            MARC4._marc4(m, k, 1536);

            // Return ciphertext
            return util.bytesToBase64(iv.concat(m));

        },

        decrypt: function (ciphertext, password) {

            var

            // Convert to bytes
                c = util.base64ToBytes(ciphertext),

            // Separate IV and message
                iv = c.splice(0, 16),

            // Generate key
                k = Crypto.PBKDF2(password, util.bytesToString(iv), 32, {asBytes: true});

            // Decrypt
            MARC4._marc4(c, k, 1536);

            // Return plaintext
            return util.bytesToString(c);

        },


        /**
         * Internal methods
         */

        // The core
        _marc4: function (m, k, drop) {

            // State variables
            var i, j, s, temp;

            // Key setup
            for (i = 0, s = []; i < 256; i++) s[i] = i;
            for (i = 0, j = 0; i < 256; i++) {

                j = (j + s[i] + k[i % k.length]) % 256;

                // Swap
                temp = s[i];
                s[i] = s[j];
                s[j] = temp;

            }

            // Clear counters
            i = j = 0;

            // Encryption
            for (var k = 0 - drop; k < m.length; k++) {

                i = (i + 1) % 256;
                j = (j + s[i]) % 256;

                // Swap
                temp = s[i];
                s[i] = s[j];
                s[j] = temp;

                // Stop here if we're still dropping keystream
                if (k < 0) continue;

                // Encrypt
                m[k] ^= s[(s[i] + s[j]) % 256];

            }

        }

    };

})();
